George h



. struts and tie-rods thereto, without deleeting them from a straight line, substantially as described.

' beam, as and for the purpose herein described and represented.

@uiten toiles aten-.t @fge Geenen n. SELLERS, or PHtENIXvILLn, PntnvsrLvANIA.-v

Letters .Patent No. 77,409, dated April 28, 1868.

IMPROVED WROUGHT-IRON ROOF-TRUSS.

TO ALL WHOM IT MAY CONCERN:

Be it knonn that I, GEORGE H. SELLERS, of Phoenixville, in the county of Chester, and State of Pennsylvania, have invent-ed certain new and useful Improvements in a WroughtlIron-Roof Truss; and I do hereby declare the following to be a fuil, clear, and exact description of the same, reference being had to the accompanying drawings making a part of this specification, in whichu Figure 1 represents a side elevation of a portion of a truss made after my general plan.

Figures 2, 3, 4, 5, and Gireprcscnt, on an enlarged scale, details'of the truss.

Similar letters of reference, where they occur in the drawings, refer to like parts of truss in all cases.

This invention relates to a wrought-iron roof-truss, wherein the shape and manner of making and putting together ofthe parts, so as to obtain the greatest strength with the smallestneiglit of material, and with due regard to the expansion and contraction of the metal, as well as in the cost of the structure, make up the general characteristics et: the invention, and constitute its value and importance.

To enable others skilled in the art te make and use my inyention, I will proceed to describe the same with reference to the drawings.

Thevtop member of the truss is a bulb-beam, A,which has a greater area ot metal in the top Bange, a, than in the bottom 'or bulb b. thus making` it theoretically correct for sustaining vertieal-.straim The' lm-lb onthe bottom ailons hetter i'abilit-ies for attaching the struts B and tie-rods e, without distorting said rods from a straight line, and avoiding transverse strains on tho rods, such as occur when Ilshaped'beams are used for suoli top members. The struts may be ot'any of the following f'orms of cross-section, viz, T, L, o, 'which forms one well known in the trade, and readily rolled. Y y

The skewhaek C, the next important eloment'oi` lthe truss, is made of two angle-brackets, d rl, riveted` or bolted, as at e, on each side of the webf of the beam A, and with or without a bottom-plate connecting these angle-pieces together. The shew-back is adapted to any angle the rafter requires, by trimming the corners g of the angie-pieces ofi', to avoid thc top flange of' the' beam. f

The tension-rods are made of bars, with enlarged ends, formed by compression in farmers or dies of any desired shape that will give a sectional area of barst the pin or boltlholc, equal to or greater than any other part of the bar. These bars are without welds, and consequently' are free fromany risks of 1vorkmanship,'the upsetting process having increased the density and strength-ofthe metal where operated on;

The manner otnnitingthe purlines h (or lath, as they are commonly cal1ed,) to the principal rafterszh, is `clearly shown in. figs. 2 and 3 A notch, z', is taken out of the purline h, and a notch,j, made in the, rafter,

where they are to he united together, which allows them to interlock one with the other, and thus aord a cheap, Y

simpleftnrl firm connection between them.

Tie-rods L", or clamps, may be used to fasten the .rafters together, and prevent the purlines from dropping ont, hnt at't'he saule time allowing room for expansion or contraction without the purlnes leaving their places.

The advantages of this notched connection between the rafters and the purlines are apparent, as it avoids v the use of rivets, bolts, and other contrivances for uniting thm. In iig. 5, various forms of perline-irons here shown, and which may be used.

Having thus fully described my invention, what I claim as new in the construction of a wrought-iron rooftruss, is-

1. Ahulb-beazn,-A, or a rafter, having a bulb, b,belon', instead of n flange, for the purpose of uniting .the

72. I also'claim securing the purlines to the ra'tter, by means of notches in each at the points where they meet, and thus make a iii-'m andsimple union between them without the use of bolts, orrivets, or other fastenn ings, and allowing roem for expansin or contraction without separating, substantially as described.

' of the web of the 3.1 also claim askew-back, made of angle-brackets d, bolted. or riveted on each side GEO. H, SELLERS.

Witnesses: i

Jos. MORGAN, Jr., Hanny C. Finnois. 

